Green Tea Research Today is a free monthly online journal that collates and summarizes the latest research about Green Tea, including details on benefits, antioxidants, weight loss, diet, side effects. | ||||||||
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GCG-Rich Tea Catechins are Effective in Lowering Cholesterol and Triglyceride Concentrations in Hyperlipidemic Rats.Lee SM, Kim CW, Kim JK, Shin HJ, Baik JH Green Tea Research Team, Food Research Institute, R&D Center, Amorepacific Corporation, 314-1 Bora-dong, Giheung-gu, Yongin-si, Gyeonggi-do, South Korea. The (-)-gallocatechin gallate (GCG) concentration in some tea beverages can account for as much as 50% of the total catechins, as a result of sterilization. The present study aims to examine the effects of GCG-rich tea catechins on hyperlipidemic rats and the mechanisms associated with regulating cholesterol metabolism in the liver. By performing heat epimerization of (-)-epigallocatechin gallate (EGCG), we manufactured a mixture of catechins that had a GCG content of approximately 50% (w/w). In sucrose-rich diet-induced hyperlipidemic rats, the GCG-rich tea catechins exhibited strong activity in reducing plasma cholesterol and triglyceride concentrations. Furthermore, the hepatic cholesterol and triglyceride concentrations that had increased as a result of the sucrose-rich diet were reduced due to GCG-rich tea catechins consumption. In order to investigate the hyperlipidemic mechanism of GCG-rich tea catechins, we examined the hepatic expressions of LDL receptor and HMG-CoA reductase in hyperlipidemic rats. We further evaluated the action of purified GCG on LDL receptor activity, which is a key contributor to the regulation of cholesterol concentrations. We found that purified GCG increased LDL receptor protein level and activity to a greater extent than EGCG. In conclusion, our study indicates that GCG-rich tea catechins in tea beverages may be effective in preventing hyperlipidemia by lowering plasma and hepatic cholesterol concentrations. Published 22 April 2008 in Lipids, 43(5): 419-29.
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